Whatsapp is, as you might guess, an app, which is HUGE in Catalunya, it's a free download and lets you message, send videos, create groups and leave voice messages, all for free and uses practically no data at all.
The odd thing is that it means that everyone has everyone's phone number. Your phone number used to be kind of a big deal, you didn't give it out to every kid in your class, nor everyone you know, but now? No big deal. Weird, no?
I saw it the other day when I had kids working with their phones to do a writing assignment, they blithely passed their phone numbers around to all and sundry. Felt weird to me, but to them, as normal as anything.
Much more connected now. Much.